PhD Synopsis Improvement in Energy Efficiency of Solar Powered … Raval.pdf · 2020. 9. 11. ·...
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Hiren D. Raval PhD Synopsis
1 of 16 Gujarat Technological University Chemical Engineering
PhD Synopsis
Improvement in Energy Efficiency of Solar Powered Reverse Osmosis by
Modification in Membrane Morphology and Recovery of Thermal Energy from
Solar Photovoltaic Panel
GUJARAT TECHNOLOGICAL UNIVERSITY
Hiren D. Raval
(Enrolment Number: 119997105001)
Supervisor: Dr. Subarna Maiti Sr. Scientist,
CSIR-Central Salt and Marine Chemicals Research Institute Bhavnagar.
Co-Supervisor: Dr. (Prof.) Abbas Ghassemi Emeritus Professor of Chemical Engineering,
Institute for Energy and the Environment/WERC New Mexico State University USA.
DPC Members
Dr. S.P. Bhatnagar
Professor and Head,
Physics Department,
MK Bhavnagar University, Bhavnagar.
Dr. AVR Reddy
Ex. Sr. Principal Scientist and
Head, Reverse Osmosis Division,
CSIR-CSMCRI Bhavnagar.
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Graphical Abstract
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A. Title of the thesis and Abstract:
Title: Improvement in Energy Efficiency of Solar Powered Reverse Osmosis by
Modification in Membrane Morphology and Recovery of Thermal Energy from Solar
Photovoltaic Panel
Abstract: Water, sanitation and hygiene was responsible for 842,000 deaths in 2012; out of
them, majority are from developing world according to the World Health Organization. Thus,
the access to safe drinking water is placed in top global challenges and more so, for the
developing country like India.
Reverse osmosis has been established as the technological solution to treat impaired
water/brackish water/seawater. Reverse Osmosis uses semi-permeable membranes to convert
saline water into fresh water. The membrane used in reverse osmosis is a thin film composite
comprising of nonwoven polyester, polysulfone and polyamide barrier layer; capable of
removing salts, bacteria, virus and suspended solids. Membrane process requires energy to
produce water since the driving force for water transport is pressure. In this way, reverse
osmosis plants need stable power supply source for its operation. Plants installed at remote
locations in developing countries where, the power supply is not constant, but endowed with
very good solar radiation intensity, solar powered reverse osmosis offers an attractive
solution. Solar powered Reverse Osmosis has been recognized as one of the promising
technologies to curtail green-house gas emissions and also for stand-alone reverse osmosis
systems at remote locations.
Reverse Osmosis has become a quite a matured technology in last decade and has been
successfully implemented at various locations in the world. However, the energy needed to
produce water has remained a major cause of concern. Energy required to produce fresh
water from seawater and brackish water are about 3-4 KWH per cubic meter and 1-2 KWH
per cubic meter respectively, depending on the total dissolved solids concentration of feed
water.
Traditional Photovoltaic (PV) collectors have a low efficiency i.e. 4–7% for the amorphous
one (a-Si) and 14–17% for the crystalline technology (c-Si). This means the large part of
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incident solar radiation is wastefully utilized in heating up the solar PV panel raising its
temperature. The mono-crystalline (m-C) and poly-crystalline (PC) cells’ electricity
production decreases when, their temperature increases because of their negative temperature
coefficient (approximately -0.4%/K). Considering the low conversion efficiency and negative
temperature coefficient of PV cells, there is a higher potential for thermal energy production
than electrical energy from a given surface of a PV module. However; the efficient utilization
of captured thermal energy is a challenge.
Many researchers realized this problem and attempted to cool the solar photovoltaic module.
Different heat transfer fluids have been used and different design configurations have been
devised. The research gap is to optimize the solar PV panel performance, achieve maximum
thermal energy recovery and also to harness the recovered heat for useful application.
Moreover; the membrane morphology can also be altered for achieving the high-flux
membrane, thereby reducing energy requirement. The present doctoral work addresses the
challenge of reducing overall energy requirement as an interdisciplinary problem and aims at
making combinations of different approaches i.e. capturing thermal energy from
photovoltaics, thereby increasing their output, utilizing the captured thermal energy in
Reverse Osmosis to increase its productivity and making the membrane surface more
hydrophilic by surface modification to achieve the least energy consumption. Thus, a multi-
pronged approach can significantly lower the energy requirement of Reverse osmosis.
Reflectors have been used to concentrate input solar radiations on PV panels world-over.
Because of the use of reflectors, the temperature of PV panels increases substantially high i.e.
approx. 90oC. The efficiency of solar PV panel drastically falls at this high temperature and
the efficient heat exchange becomes imperative to bring down the temperature. Moreover, the
life of solar panel also decreases if operated at very high temperature. The present work is
aimed at designing and implementing the heat exchange to bring down the temperature of a
solar panel where it works at its optimal efficiency. A study has been made regarding the heat
extraction aspects from solar PV panels to increase the temperature of feed water for
desalination.
At high temperature feed water, the permeability of membrane increases with a slight decline
in selectivity. This can be implemented for low salinity feed water for which lower selectivity
of membrane will be acceptable to avoid re-mineralization of product water. Moreover, the
present work also studied the membrane modification to tailor-make the membrane for very
high permeability that requires lower pressure to generate the same quantity of water.
Moreover, such membrane is more temperature-sensitive. Thus, rise in water flux with rise in
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temperature is more pronounced. Such low pressure membrane will be suited for solar
powered brackish water RO plant since the array surface area required will be low. In this
way, the present PhD work takes solar powered RO in a holistic way to achieve overall
energy efficiency by following:
1. Extracting waste heat from solar PV panels
Direct cooling with water has been attempted for controlling the temperature of
photovoltaic panel. Two experimental approaches were undertaken: cooling from top
of the panel with insulation on the back and sides to tap the maximum possible
thermal energy, cooling from back side of the panel. It is observed that there is an
improvement in panel performance and simultaneously there is an increase in water
temperature in both the cases.
ANSYS Computational fluid dynamics software has been used to simulate the panel
temperature and the simulated temperature has also been experimentally validated.
2. Utilization of captured thermal energy:
The recovered thermal energy has been capitalized to elevate the temperature of feed
water to reverse osmosis. In other words; the cooling water in objective 1 was the
feed water to reverse osmosis. As a result of heat transfer to feed water, the
temperature of feed water increases. At higher temperature, the viscosity of water
decreases and therefore the resistance to flow decreases. Thus, the higher temperature
feed water improves the trans-membrane water flux at applied pressure. Thus, energy
consumption to produce definite quantity of fresh water decreases, which have been
quantified.
3. Modification in polyamide layer of thin film composite membrane to improve
permeability:
Improvement in TFC RO Membrane permeability is very important alternative for
reducing the overall energy consumption of Reverse osmosis. A step change in
membrane permeability has been achieved by surface modification on account of
chemical reaction i.e. controlled oxidation with sodium hypochlorite, polyamide-
chitosan composite membrane (with increased water permeance and selectivity). Such
membrane was found to be more temperature-sensitive i.e. higher rise in water flux
with given rise in water temperature. The objective is to make the process highly
energy efficient and frugal for reverse osmosis application.
This interdisciplinary approach is novel and demonstrated the substantial decline in
energy consumption of renewable powered desalination. It will lead to energy
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efficient solution and thus increase the green quotient of the reverse osmosis plants.
Thus, this interdisciplinary approach makes the overall process very attractive from
the energy consumption point of view and all the objectives of the PhD work have
been achieved.
A. Brief description on the state of the art of research topic:
Solar energy is one of the most significant, unlimited, clean and environmentally
friendly source of renewable energy. The rapidly developing technology as of date is
solar photovoltaics (PV). The major impediment to its wide popularity is low
efficiency of converting the solar energy into electricity i.e. 5-17%. More than 80% of
the absorbed solar radiation gets converted by the PV cells as waste heat. This heat is
generated in two ways. Firstly, the power corresponding to I 2R, as an outcome of the
current (I) flowing through the resistance, R of the solar cell. Secondly, the thermal
energy which represents the variation in the absorbed photons and the electrical
energy generated out of the electron–hole pairs. Cell temperature is of vital
significance for performance of PV cells in a panel [1, 2]. If the temperature of solar
PV panel increases, its efficiency to convert solar radiation into electric current
decreases because of its negative temperature co-efficient (about -0.4% per o
C rise in
temperature) with temperature. Temperature dependence of photovoltaic performance
and energy conversion in solar PV panels are investigated by many researchers. In
gist, the solar photovoltaic panel produces more thermal energy than the electrical
energy.
J.K. Tonui and Y. Tripanagnostopoulos attempted air cooling of solar PV panel and
for performance improvement of solar PV/T collector with natural flow operation.
Performance studies on a finned double-pass photovoltaic-thermal (PV/T) solar
collector demonstrated that fins improve efficiency of heat transfer by air cooling [3].
Several researchers attempted to control the temperature of the PV panel. Desiccant
cooling system relevant to hot and humid climate equipped with both single glazed
standard air and hybrid photovoltaic thermal collector has been studied [4]. A liquid
coolant with the heat exchanger system housed within the photovoltaic module to
exclude the unwanted solar radiation in order to minimize overheating of the cells [5].
A cooling method for the solar cells under concentrated solar flux was proposed
where; the additional heat was removed from both the front and back surfaces of the
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module by directly immersing the cells in a dielectric liquid [6]. Unique profile for the
reflecting surfaces was developed in such a way that the solar cells are evenly
illuminated under any degree of concentration [7].
Liquid immersion cooling was found to eliminate the thermal resistance of back
cooling to improve cell performance [8]. Tanaka studied that the use of a shallow
liquid layer or a gel layer surrounding solar cells for trapping the radiation and also to
wet the cell surface [9, 10, 11]. Carcangiu and co-workers patented an immersed
liquid photovoltaic panel. The panel uses a liquid-tight chamber to house solar cells
immersed in a poly-dimethylsilicone liquid, being circulated [12].
Ignacio and co-workers used curved, optically transparent covers to enhance the
concentrating effect of the immersion dielectric liquid [13]. Falbel patented a
surrounding reflective surface for a solar cell, which reflects back the light rays that
are not absorbed by the solar cell [14]. Besides the liquid and gel, Cherney et al.
attempted to extend the refractive medium to a solid [15]. Using water as the
immersion liquid, the panels are configured with liquid super-concentrators having
outwardly disposed liquid imaging lenses [16].
Liquid immersion offers several advantages e.g. the optical and surface wetting, the
direct contact between cells and their surrounding liquid decreases the thermal
resistance, especially for cells at high concentrations. The conventional cooling has
the thermal resistance; eliminating the thermal resistance of the contact wall between
solar cell and fluid, the cells can be effectively cooled down for a desirable sunlight-
to-electricity conversion efficiency [17].
The plant leaves convert the solar energy into the food; an attempt to mimic the same
was done to understand how they control temperature when exposed to sun [18]. Air
is very widely studied coolant; an active cooling of PV module by blowing air above
the module with Computational fluid dynamics analysis has been attempted [19].
It has been reported that the thin film of water above the solar photovoltaic panel
improves the photovoltaic panel performance. However, the comparison with the
modelled data is missing and the energy efficiency derived out of the system has not
been worked out.[20]
Researcher attempted to improve the photovoltaic panel
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efficiency by direct water cooling; however the application of recovered energy has
not been explored [21].
Despite the extensive research on heat transfer from solar PV panel, modeling and
experimental validation of solar panel heat transfer with water cooling from top
surface with overall energy perspective remains the research gap and the present work
addresses the same. In addition to that, the membrane morphological changes for
higher hydrophilicity and lower energy consumption will make the solar powered
reverse osmosis an attractive solution. The present work also demonstrates that the
membrane surface can be made more hydrophilic in order to achieve higher
productivity and thus, lower the energy consumption.
C. Definition of the problem:
The present doctoral work addresses the following problems:
1) Can we extract the waste thermal energy from solar PV panels in order to
control its temperature and increase its efficiency?
2) Can we utilize the captured thermal energy for useful application?
3) Can we modify modify the polyamide layer of thin film composite
membrane to improve permeability and thereby decrease energy
consumption of Reverse Osmosis?
It systematically studies each aspect of the problem to suggest the solution.
D. Objective and scope of work:
Objectives:
1. Study heat transfer aspects of solar photovoltaic panel from theoretical and
experimental point of view to understand the rise in temperature of solar photovoltaic
panel and also study the photovoltaic panel performance with and without heat
transfer.
2. Capture the thermal energy and study its application for useful purpose. The captured
energy should be directly utilized in order to minimize its loss.
3. Study the Thin film composite Reverse Osmosis membrane and explore the way to
increase its permeability and thereby decrease the energy consumption of Reverse
Osmosis.
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Scope of work: The present doctoral work addresses each objective as mentioned above
and studies the heat transfer aspects theoretically by ANSYS Computational fluid
dynamics software to evaluate the temperature of photovoltaic panel and also
experimentally validates the data. It also demonstrates that the captured thermal energy
can be utilized directly in reverse osmosis to achieve higher energy efficiency. It studies
the membrane morphology and finds the way to increase the hydrophilicity of the
membrane and makes the reverse osmosis very low energy intensive.
E. Original contribution by the thesis:
The original contribution is manifested by 4 international peer-reviewed papers those
have been published out of this doctoral work as shown below:
1. Hiren D. Raval*, Pranav S. Rana, Subarna Maiti A novel high-flux thin film
composite reverse osmosis membrane modified by chitosan for advanced water
treatment RSC Advances 5 (2015) 6687-6694
doi: 10.1039/C4RA12610F (5-YEAR IMPACT FACTOR: 3.907)
2. Hiren D. Raval*, Subarna Maiti Ultra- low energy Reverse osmosis with thermal
energy recovery from photovoltaic panel cooling and TFC RO membrane
modification Desalination and Water Treatment 57 (2016) 1-10
Published online doi: 10.1080/19443994.2014.993725 (5-YEAR IMPACT
FACTOR: 1.017)
3. Hiren D. Raval*, Subarna Maiti*, Ashish Mittal Computational fluid dynamics
analysis and experimental validation of improvement in overall energy efficiency
of a solar photovoltaic panel by thermal energy recovery Journal of renewable and
sustainable energy 6 (2014) 033138
doi: 10.1063/1.4885178 (5-YEAR IMPACT FACTOR: 1.149)
4. Hiren D. Raval*, Subarna Maiti, A novel photovoltaic powered Reverse Osmosis
with improved productivity of Reverse osmosis and photovoltaic panel Journal of
Membrane Science and Research 1 (2015) 113-117 (New peer-reviewed journal,
expecting impact factor)
Presentation in an International conference (USA)
H.D. Raval*, S. Maiti, A. Ghassemi, L. Karimi (2014) “Options for improving attractiveness
of renewable energy powered desalination” at AICHE Annual meeting-2014 Atlanta, GA,
USA
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F. Methodology of research, results/comparison
The methodology involves the experimental as well as modelling work. The solar
photovoltaic panel was cooled by flowing water from top as well as bottom at
different flow rates. The temperatures of panel with and without cooling were
monitored over a period of time. Moreover, the theoretical study was made by
ANSYS computational fluid dynamics software to simulate the temperature of
photovoltaic panel with given solar insolation. Simulated data were validated by
experimental data as they were in close conformity.
The rise in temperature of water was monitored. The heated water was subjected to
domestic reverse osmosis membrane element. The performance of reverse osmosis
membrane element (i.e. solute rejection/flow rate) was monitored during the
experiment. The membrane element was also treated with sodium hypochlorite at pH
11.0 to increase its productivity and the performance of membrane element was
monitored. Thin film composite RO membrane was also modified by a supra-
molecular assembly of chitosan over polyamide to enhance the productivity and
temperature sensitivity of the membrane. Such modified membranes and virgin TFC
RO membrane were characterized: surface morphology by atomic force microscope,
chemical structural changes by attenuated total reflectance-Fourier Transform Infrared
Spectroscopy, surface hydrophilicity by contact angle, surface charge by Zeta
potential analyzer.
Following conclusions were derived out of the studies:
Photovoltaic panel temperature can be effectively controlled by transferring heat from
top at low flow rate e.g. 1 and 2 Liters per minute and insulation at the back surface
and sides. The insulation makes sure that the heat is not lost from bottom and the
direction of heat transfer is bottom-up. CFD analysis is in close confirmation with
experimental validation for the panel temperature.
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It is demonstrated for the first time that the refraction of incident solar radiation while
striking to PV panel through the water film is beneficial. Narrowing the span of angle
striking to the panel during the day is better from the point of view of panel
performance.
The rise in water temperature reported indicates that there is a potential to tap the
thermal energy. The higher temperature water can be used for desalination systems
like membrane distillation, reverse osmosis etc. The higher temperature water can be
used for reverse osmosis where, higher feed water temperature offers the advantage of
higher product water flow.
Overall energy efficiency has been increased from about 6% to 40% by direct cooling
the array surface of PV panel from top at 1 liter per minute flow.
The feed water to reverse osmosis was used as coolant of PV system. The heated feed
water was directly passed through reverse osmosis membrane element. Membrane
modifications were made to make it more hydrophilic. This approach resulted in ultra-
low energy reverse osmosis with following conclusions:
Controlled oxidation of polyamide layer at high pH resulted in improved flow
performance of the membrane. The TFC RO membrane became more hydrophilic by
this treatment. This can synergistically increase the flow of domestic RO membrane
module along with higher temperature feed water.
Overall 67.86% rise in flow with ca. 1% decline in solute rejection has been observed
by increasing the feed water temperature by 12oC and treating the membrane with
sodium hypochlorite solution at exposure level of 162.5 ppm-hour at 11.5 pH. The
novel combination of altering the membrane morphology and using high temperature
feed water improved the overall energy efficiency; the energy requirement decreased
by about 40%. Also, the overall recovery of domestic RO system increases as the
concentrate is re-circulated back to the panel.
Cooling the photovoltaic from the back surface (other than the array surface) of
photovoltaic panel and directly utilizing the water for reverse osmosis demonstrated
the following results:
Domestic Reverse Osmosis (RO) membrane permeate flow rate increased from 85
ml/minute to 118 ml/minute when the feed water temperature increased from 35oC to
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45oC. The feed water viscosity decreases at higher temperature; thus the resistance to
flow decreases. Thus, the tapped thermal energy in feed water improved the
productivity of reverse osmosis membrane.
The cooling water can control the temperature of PV panel. The difference in the
average temperature of PV panel with cooling and without cooling is at its highest at
1200 noon when, the temperature of PV panel with cooling was 34.3oC and without
cooling was 59.1oC. The power produced by PV panel increased with cooling on the
back side as the temperature of PV panel kept lower.
Total water output over 7 hour period (from 1000 Hrs to 1700 Hrs) was increased by
20% by heating feed water for solar photovoltaic panel cooling.
It has been demonstrated that the specific energy consumption of reverse osmosis
decreases by ca. 28% when the feed water temperature increases by 10oC.
The energy consumption for reverse osmosis can be decreased by making very high
permeability reverse osmosis membrane and putting it in use. The thin film composite
RO membrane can be modified to make a very high flux membrane by successive
chemical treatment of sodium hypochlorite and chitosan to make the hydrophilic
supra-molecular assembly. Such a composite membrane demonstrated lower contact
angle and higher hydrophilicity. Following conclusions were derived:
The trans-membrane flux increased from 14 gallons per square feet per day (gfd) to
30 gfd with increase in NaCl solute rejection from 92% to 95%, whereas the flux
increased from 16 gfd to 28 gfd with increase in MgCl2 rejection from 86.36% to
95.06% when the membrane was exposed to 1250 mg/l sodium hypochlorite at pH
11.0 for 30 minutes followed by 1000 mg/l chitosan solution at pH 2.5 for 60 minutes.
The trans-membrane flux increased from 14 gfd to 49 gfd with decline in NaCl solute
rejection from 92% to 86.36%, whereas, the flux increased from 16 gfd to 43.5 gfd
with a slight decline in MgCl2 rejection from 86.36% to 85.46% when the membrane
was exposed to 1250 mg/l sodium hypochlorite at pH 11.0 for 60 minutes followed by
1000 mg/l chitosan solution at pH 2.5 for 60 minutes. This showed the longer sodium
hypochlorite exposure compromises on membrane selectivity.
Zeta potential of the thin film composite RO membrane decreased from -33.8 mV to -
37.42 mV and roughness decreased from 225 nm to 117 nm when the membrane was
exposed to 30 minutes, 1250 mg/l sodium hypochlorite at pH 11.0 and 1000 mg/l
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chitosan at pH 2.5. This shows improvement in divalent ion as the charge becomes
more negative.
The average contact angle decreased from 49o to 32.5
o when membrane was exposed
to 30 minutes, 1250 mg/l sodium hypochlorite at pH 11.0 and 1000 mg/l chitosan for
60 minutes at pH 2.5. This demonstrates that hydrophilicity of the membrane
increased.
Presence of –OH group and modification in –CO- group in polyamide structure shows
the supra-molecular assembly of chitosan over polyamide.
1000 mg/l chitosan treated membrane for 60 minutes at pH 2.5 after 1250 mg/l
sodium hypochlorite treated membrane at pH 11.0 was more temperature sensitive as
compared to TFC RO membrane and demonstrated 5.56% rise in flux per oC rise in
feed water temperature. Such a modified membrane may be used in solar photovoltaic
powered desalination where, the feed water can capture thermal energy from solar
photovoltaic to control its temperature and thus gets heated. The low grade captured
thermal energy can be utilized synergistically to increase the permeability of the
membrane.
Thus, this doctoral research demonstrates that interdisciplinary approach is essential
to make the substantial decline in energy requirement of solar powered reverse
osmosis and make it an attractive solution.
G. Achievements with respect to objectives
Objective Published Paper for the objective
Study heat transfer aspects of solar
photovoltaic panel from
theoretical and experimental point
of view to understand the rise in
temperature of solar photovoltaic
panel and also study the
photovoltaic panel performance
with and without heat transfer. -
ACHIEVED
1. Hiren D. Raval*, Subarna Maiti*,
Ashish Mittal Computational
fluid dynamics analysis and
experimental validation of
improvement in overall energy
efficiency of a solar photovoltaic
panel by thermal energy recovery
Journal of renewable and
sustainable energy 6 (2014) 033138
doi: 10.1063/1.4885178
2. Hiren D. Raval*, Subarna Maiti,
Hiren D. Raval PhD Synopsis
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A novel photovoltaic powered
Reverse Osmosis with improved
productivity of Reverse osmosis
and photovoltaic panel Journal of
Membrane Science and Research 1
(2015) 113-117 (Peer reviewed
international Journal)
Capture the thermal energy and study its
application for useful purpose. The
captured energy should be directly utilized
in order to minimize its loss. -
ACHIEVED
Hiren D. Raval*, Subarna Maiti Ultra-
low energy Reverse osmosis with
thermal energy recovery from
photovoltaic panel cooling and TFC RO
membrane modification Desalination and
Water Treatment 57 (2016) 1-10 Published
online doi:
10.1080/19443994.2014.993725
Study the Thin film composite Reverse
Osmosis membrane and explore the way
to increase its permeability and thereby
decrease the energy consumption of
reverse osmosis. - ACHIEVED
Hiren D. Raval*, Pranav S. Rana, Subarna
Maiti A novel high-flux thin film
composite reverse osmosis membrane
modified by chitosan for advanced
water treatment RSC Advances 5 (2015)
6687-6694 doi: 10.1039/C4RA12610F
H. Conclusion: All the objectives are addressed and peer reviewed, international
papers with impact factors have been published. Thus, the synopsis of doctoral work
is hereby, submitted to Gujarat Technological University.
I. Copies of papers published and a List of all publications arising from the
thesis
Copies of the papers published are attached herewith.
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1. Hiren D. Raval*, Pranav S. Rana, Subarna Maiti A novel high-flux thin film
composite reverse osmosis membrane modified by chitosan for advanced
water treatment RSC Advances 5 (2015) 6687-6694
doi: 10.1039/C4RA12610F
(5-YEAR IMPACT FACTOR: 3.907)
2. Hiren D. Raval*, Subarna Maiti Ultra- low energy Reverse osmosis with
thermal energy recovery from photovoltaic panel cooling and TFC RO
membrane modification Desalination and Water Treatment 57 (2016) 1-10
Published online doi: 10.1080/19443994.2014.993725
(5-YEAR IMPACT FACTOR: 1.017)
3. Hiren D. Raval*, Subarna Maiti*, Ashish Mittal Computational fluid dynamics
analysis and experimental validation of improvement in overall energy
efficiency of a solar photovoltaic panel by thermal energy recovery Journal of
renewable and sustainable energy 6 (2014) 033138
doi: 10.1063/1.4885178
(5-YEAR IMPACT FACTOR: 1.149)
4. Hiren D. Raval*, Subarna Maiti, A novel photovoltaic powered Reverse
Osmosis with improved productivity of Reverse osmosis and photovoltaic
panel Journal of Membrane Science and Research 1 (2015) 113-117 (NEW
INTERNATIONAL PEER REVIEWED JOURNAL EXPECTING IMPACT
FACTOR)
J. Patents – Nil
K. References
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Hiren D. Raval PhD Synopsis
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